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PTO/SB/05 (4/98p 

Please type a plus sign (+) inside this box -> 1+ 1 Approved for use through 09/30/2000. OMB 0651-0032CT, 

1 1 Patent and Trademark Office: U.S. DEPARTMENT OF COMMERCfjP 


f UTILITY 

PATENT APPLICATION 
TRANSMITTAL 

lOnfy for new nonprovisional applications under 37 C.F.R. § 1.53(b)) 


Attorney Docket No. 


ACS-5349S (21061) * 


First Inventor or Application Identifier Brent Belding 


Title 


DETACHABLE SHEATH... 


Expr 


9ss Mail Label No. 


EL590182299US A 


APPLICATION ELEMENTS 

See MPEP chapter 600 concerning utility patent application contents. 


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H* Fee Transmittal Form (e.g., PTO/SB/17) 
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| X | Specification [Total Pagesl 4 2 U 
(preferred arrangement set forth below) ' ■ 

- Descriptive title of the Invention 

- Cross References to Related Applications 

- Statement Regarding Fed sponsored R&D 

- Reference to Microfiche Appendix 

- Background of the Invention 

- Brief Summary of the Invention 

- Brief Description of the Drawings (if filed) 

- Detailed Description 

- Claim(s) 

- Abstract of the Disclosure 

3. | X | Drawing(s) (35 U.S. C. 113) [Total Sheets 

4. Oath or Declaration [Total Pages \ 51 
a. | | Newly executed (original or copy) 

□ DELETION OF INVENTORfSl 
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inventor(s) named in the prior application 
see 37 C.F.R. §§ 1.63(d)(2) and 1.33(b). 



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ACCOMPANYING APPLICATION PARTS 



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For CONTINUATION or DIVISIONAL APPS only : The entire disclosure of the prior application, from which an oath or declaration is supplied 
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Fulwider Patton Lee nmmVV^LP 



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APPLICATION 



of 

BRENT BELDING 
BRIAN P. CAHILL 
JEFFREY T. ELLIS 
RICHARD J. FOUST 
ARKADY KOKISH 
FLORENCIA LIM 
and 
CHI LONG 
for 

UNITED STATES LETTERS PATENT 



on 



DETACHABLE SHEATH TO PROVIDE 
PRE-DEPLOYMENT STENT SECURITY 
AND ENHANCED DELIVERY PRECISION 



Docket No. ACS-53498 (21061) 
Sheets of Drawing Figures: Nine (9) 
USPTO Customer Number: 24201 

Attorneys 

FULWIDER PATTON LEE & UTECHT, LLP 
Howard Hughes Center, 6060 Center Drive, Tenth Floor 
Los Angeles, California 90045 

Express Mail No. EL590182299US 



DETACHABLE SHEATH TO PROVIDE 
PRE-DEPLOYMENT STENT SECURITY 
AND ENHANCED DELIVERY PRECISION 



BACKGROUND OF THE INVENTION 

This invention relates to apparatus and methods for the treatment of 
body lumens, and particularly to delivery systems for endoprostheses. More 
particularly, the invention relates to retaining devices for removably securing stents to 
catheters during delivery through human vasculature. The present invention also is 
directed to a delivery system for self-expanding stents which facilitates minimal stent 
movement during deployment to achieve more accurate stent placement within the 
patient's vasculature. 

Several interventional treatment modalities are presently used for heart 
disease including balloon and laser angioplasty, atherectomy and by -pass surgery. In 
a typical cardiovascular intervention, a guiding catheter having a preformed distal tip 
is percutaneously introduced over a 0.035" wire that has been placed in the 
vasculature through a guiding sheath into an artery and advanced within the 
cardiovascular system until the distal tip of the guiding catheter is seated in the ostium 
of a coronary artery. The 0.035" wire is removed and a 0.014" guidewire is advanced 
distal to the treatment area. Then a dilatation catheter is back-loaded onto the 0.014" 
guidewire and tracked to the treatment area through the guiding catheter. Once in 
position across the lesion, the balloon is inflated to a predetermined size with 
radiopaque liquid at relatively high pressure (e.g., greater than four atmospheres) to 
compress the plaque of the lesion and to otherwise expand the inner lumen of the 
artery. 

Further details of dilatation catheters, guidewires, and devices 
associated therewith for angioplasty procedures have been known for a number of 
years, and by way of example, several forms of such devices can be found in U.S. 
Patent No. 4,323,071 (Simpson-Robert); U.S. Patent No. 4,439,185 (Lindquist); U.S. 



_2- Docket No. ACS-53498 (21061) 

latent No. 4,516,972 (Samson); U.S. Patent No. 4,538,622 (Samson, et al.); U.S. 
Patent No. 4,554,929 (Samson, et al.); U.S. Patent No. 4,616,652 (Simpson); U.S. 
Patent No. 4,638,805 (Powell); U.S. Patent No. 4,748,982 (Horzewski, et al.); U.S. 
Patent No. 5,507,768 (Lau, et al.); U.S. Patent No. 5,514,154 (Lau, et al.); U.S. Patent 
No. 5,451,233 (Yock); and U.S. Patent No. 5,458,615 (Klemm, et al.); U.S. Patent 
No. 5,700,286 (Tartaglia, et al.). 

A focus of recent development work in the treatment of heart disease 
has been directed to endoprosthetic devices called stents. Stents are generally 
cylindrically shaped intravascular devices which are placed within an artery to hold it 
open. The device can be used to reduce the likelihood of restenosis and to maintain 
the patency of a blood vessel immediately after intravascular treatments. In some 
circumstances, they can also be used as the primary treatment device where they are 
expanded to dilate a stenosis and then left in place. 

Prior art stents typically fall into two general categories of construction. 
The first type of stent is expandable upon application of the controlled force, often 
through the inflation of the balloon portion of a dilatation catheter which, upon 
inflation of the balloon or other expansion means, expands the compressed stent to a 
larger diameter to be left in place within the artery at the target site. The second type 
of stent is a self-expanding stent formed from shape-memory metals or super-elastic 
nickel titanium (NiTi) alloys which will automatically expand from a compressed 
state when the stent is advanced out of the distal end of the delivery catheter into the 
body lumen. Such stents manufactured from expandable heat-sensitive materials 
allow for phase transformation of the materials to occur, resulting in the expansion 
and contraction of the stents. 

One method and system developed for delivering stents to desired 
locations within the patient's body lumen involves advancing the stent delivery system 
through the patient's vascular system until the stent is positioned within the treatment 
area, and then inflating the expandable member on the catheter to expand the stent 



_3„ Docket No. ACS-53498 (21061) 

within the blood vessel. The expandable member is then deflated and the catheter 
withdrawn, leaving the expanded stent within the blood vessel, holding open the 
passageway thereof. 

However, retaining the position of the stent in the proper location on the 
5 expandable member while advancing the catheter through the body lumen can be 

compromised by tortuous vessels, calcified arteries, or previously placed stents. If the 
stent is dislodged from or moved relative to the expandable member, then the system 
will not correctly deliver the stent into the body lumen. This may require retrieval of 
the stent, repeat of the procedure, or surgery. All of these possibilities may adversely 
1 0 O affect the patient's health. 

m Since the catheter and stent will be traveling through the patient's 

fy vasculature, and possibly through the coronary arteries, the stent must have a small 
2 delivery diameter and must be firmly attached to the catheter until the physician is 
Ms ready to implant it. Thus, the stent must be loaded onto the catheter so that it does not 
150 interfere with delivery, and it must not come off of the catheter until it is implanted in 
O the artery. 

S Different methods have been attempted to maintain the position of the 

M stent on the expandable member. One such method involves a protective sheath 
surrounding the catheter and stent assembly, the sheath being retracted prior to 
20 inflation of the expandable member. The use of the sheath, however, increases the 

profile of the catheter assembly which must traverse stenosed and diseased vessels. In 
addition, the sheath increases the complexity of delivering the stent by requiring the 
physician to withdraw the sheath prior to inflation of the expandable member. It 
would be an improvement to use a technique which does not substantially increase the 
25 overall profile of the catheter assembly and does not require further manipulation by 
the physician. 

There can be some additional problems associated when implanting 
self-expanding stents within the patient's vasculature. Some prior art stent delivery 



_4- Docket No. ACS-53498 (21061) 

systems for self-expanding stents including an inner lumen upon which the 
compressed or collapsed stent is mounted and an outer restraining sheath which is 
eventually placed over the compressed stent prior to deployment. When the stent is to 
be deployed in the body vessel, the outer sheath is moved in relation to the inner 
lumen to "uncover" the compressed stent, allowing the stent to move to its expanded 
condition. Some delivery systems utilize a "push-pull" technique in which the outer 
sheath is retractable while the inner sheath is pushed forward. Still other systems use 
an actuating wire which is attached to the outer sheath. When the actuating wire is 
pulled to retract the outer sheath over the collapsed stent, the inner lumen must remain 
stationary, preventing the stent from moving axially within the body vessel. 

There have been problems associated with the prior art delivery systems 
for self-expanding stents. For example, systems which rely on a "push-pull" design 
can experience movement of the compressed stent within the body vessel when the 
inner lumen is pushed forward which can lead to inaccurate positioning and, in some 
cases, possible perforation of the vessel wall by a protruding end of the stent. 
Systems which utilize the actuating wire design tend to follow the radius of curvature 
when placed in the curved anatomy of a patient. As the wire is actuated, tension and 
delivery systems can cause the wire to straighten. As the system straightens, the 
position of the stent changes because of the length of the catheter no longer conforms 
to the curvature of the anatomy. This changes the geometry of the system within the 
anatomy and can also lead to inaccurate stent positioning. 

Since proper positioning of the stent is critical to the performance of 
the stent, it is imperative that the physician knows exactly where the stent will be 
placed upon deployment. Some existing self-expanding stents can store energy 
axially as the outer restraining sheath is retracted. Frictional force generated as the 
outer sheath is retracted over the compressed stent can cause the stent to act somewhat 
like a spring, storing energy as the frictional forces act on the stent. This stored 
energy can be released as the stent expands beyond the end of the sheath, causing the 



_5- Docket No. ACS-53498 (21061) 

stent to move or "jump" from the catheter away from the desired position, resulting in 
inaccurate stent placement. The amount of energy stored is dependent on the 
flexibility of the stent and the friction between the stent and outer sheath. 

What has been needed and heretofore unavailable is a satisfactory 
5 retaining device for maintaining an endoprosthesis in a desired location on a delivery 
catheter without significantly increasing the overall profile of the catheter assembly, 
without requiring manipulation of the retaining device by the physician and without 
requiring the retaining device to expand with an expandable member of the catheter 
assembly. This device is also intended to give the user 100% confidence that the stent 
1 0 y| will not be dislodged prior to placement and deployment in the treatment segment. 
Hi There is also a need for a stent delivery system that facilitates minimal movement 
^ during deployment of a self-expanding stent to provide for more accurate stent 
^ placement. Such a delivery system should help prevent the self-expanding stent from 
s "jumping" from the delivery system to allow for more accurate positioning within the 

15 Co body lumen. The present invention satisfies these and other needs. 

pi 

SUMMARY OF THE INVENTION 

Briefly, and in general terms, the present invention is directed to a 
catheter assembly for delivering an endoprosthesis within a body lumen. More 
particularly, the invention relates to a delivery catheter assembly including a 

20 detachable sheath for removably securing an endoprosthesis onto an expandable 

member (for example, a balloon). The detachable sheath is associated with a catheter 
assembly having an expandable member therein, whereby inflation of the expandable 
member ruptures the detachable sheath, thereby exposing the endoprosthesis for 
implantation into a body lumen. Alternatively, the detachable sheath may be inflated 

25 separately from the expandable member, and may be manually retracted from the 



„6_ Docket No. ACS-53498 (21061) 

endoprosthesis. The detachable sheath prevents movement of the endoprosthesis 
relative to the catheter assembly during deployment in a body lumen, such as a 
patient's vasculature, by covering the endoprosthesis until the endoprosthesis is 
positioned at the desired location within the body lumen. The retaining device of the 
present invention can be used with the common configurations of delivery catheter 
assemblies, including over-the-wire intravascular catheters, rapid exchange 
intravascular catheters, monorail intravascular catheters, and perfusion-type catheters. 

In one embodiment of the invention, the detachable sheath is configured 
to removably secure a stent to a delivery catheter assembly. Such a catheter assembly 
includes a catheter tube, wherein a balloon is formed on the distal end portion of the 
catheter tube and a stent is disposed on the balloon. A sheath is secured to the distal 
end portion of the catheter tube, such that the sheath is stretched over the balloon and 
over the stent. The sheath includes a weakened section configured to rupture during 
inflation of the balloon. In addition, the sheath may include a plurality of 
circumferential perforations to enhance rupture of the sheath at a desired location. In 
an alternative embodiment of the catheter assembly, the proximal end portion of the 
sheath is positioned proximal to the proximal end portion of the catheter tube, and the 
distal end portion of the sheath is configured with a weakened section and secured to 
the distal end portion of the catheter tube. Such a detachable sheath may further 
include an inflation port positioned proximate the proximal end portion of the sheath. 
The proximal end portion of such a sheath may be secured to the proximal end portion 
of the catheter tube, wherein the sheath is stretched prior to securing the sheath to the 
catheter tube. 

The invention results in a simplified method of delivering an 
endoprosthesis — for example, a stent — into a body lumen — for example, a human 
vasculature. A delivery catheter assembly is provided that includes a catheter 
assembly having an expandable member associated with the distal end portion of the 
catheter. An endoprosthesis is disposed on the expandable member, and a detachable 



_7- Docket No. ACS-53498 (21061) 

sheath is disposed on the catheter and over the endoprosthesis, wherein the sheath is 
configured to rupture during expansion of the expandable member. The catheter 
assembly is inserted into the vasculature and manipulated so that the distal end of the 
catheter tube is positioned proximal to a desired location in the vasculature, such as at 
a lesion or stenosis in a coronary artery. The detachable sheath firmly holds the stent 
onto the expandable member while traversing the vasculature. The expandable 
member (in some configurations, a dilatation balloon) is inflated at the desired 
location in the vasculature, thereby rupturing the sheath and exposing the stent. 
Alternatively, the sheath may be separately inflated from the expandable member, 
and/or may be retracted manually. The expandable member is further inflated, 
thereby expanding and implanting the stent at the desired location. The expandable 
member is then deflated, the stent is released and the remainder of the catheter 
assembly, including the ruptured sheath is withdrawn, leaving the stent permanently 
implanted within the vasculature. 

The prosthesis could be, for example, a self-expanding stent which 
would expand once the detachable sheath has been ruptured by the expansion of the 
expandable member. In this fashion, the self-expanding stent starts to deploy as soon 
as the sheath ruptures allowing the stent to be deployed within the patient's 
vasculature. The structure of the detachable sheath and catheter would be 
substantially the same for a self-expanding stent as it would be for the balloon 
expandable stent, except that the sheath may have to resist the forces exerted by the 
self-expanding stent as it remains in its collapsed position until the stent is ready to be 
deployed. For this reason, the detachable sheath may have to be made from a suitably 
stronger material to maintain the self-expanding stent in its collapsed position until 
the expandable member is expanded to rupture the sheath. A delivery catheter 
assembly made in accordance with the present invention for use in deploying a self- 
expanding stent should help prevent the stent from "jumping" from the catheter 



_g_ Docket No. ACS-53498 (21061) 

during deployment to allow for more accurate placement within the patient's 
vasculature. 

Other features and advantages of the invention will become apparent 
from the following detailed description, taken in conjunction with the accompanying 
5 drawings, which illustrate, by way of example, the features of the invention. 



BRIEF DESCRIPTION OF THE DRAWINGS 



p j FIGURE 1 depicts a longitudinal plan view of an embodiment of a 

W catheter assembly including a detachable sheath of the present invention. 

I FIG. 2 depicts a cross-sectional view along lines 2-2 of FIG. 1. 

1()M FIG. 3 depicts a partial longitudinal plan view of a distal portion of a 

O catheter assembly including a detachable sheath of the present invention, including a 
hidden view of a stent mounted on a balloon. 



FIG. 4 depicts a partial longitudinal plan view of the catheter assembly 
of FIG. 3, wherein the detachable sheath has been ruptured, thereby exposing the stent 
15 and the balloon. 

FIG. 5 depicts a partial longitudinal plan view of the catheter assembly 
of FIG. 3, wherein the detachable sheath has retracted longitudinally, folly exposing 
the stent and the balloon. 



20 



FIG. 6 depicts a partial longitudinal plan view of the catheter assembly 
of FIG. 3, wherein the detachable sheath has been ruptured as a result of the balloon 



_9- Docket No. ACS-53498 (21061) 

expanding first at the proximal and distal edges, thereby exposing the stent and the 
balloon. 

FIG. 7 A depicts a longitudinal plan view in partial cross-section of an 
intravascular catheter assembly including an alternative embodiment of a detachable 
sheath of the present the invention, wherein the detachable sheath extends from 
proximate the proximal end of the catheter assembly. 

FIG. 7B depicts a partial longitudinal plan view of a distal portion of the 
catheter assembly of FIG. 7A. 

FIG. 8 depicts a longitudinal plan view in partial cross-section of an 
over-the-wire intravascular catheter assembly including a detachable sheath of the 
present the invention. 

FIG. 9 depicts a longitudinal plan view in partial cross-section of a rapid 
exchange intravascular catheter assembly including a detachable sheath of the present 
the invention. 

FIG. 10 depicts a longitudinal plan view of a stent delivery catheter 
assembly, including a detachable sheath of the present invention, wherein a stent is 
shown in a hidden view. 

FIG. 1 1 depicts a longitudinal plan view of a stent delivery catheter 
assembly, including a detachable sheath of the present invention, partially inserted 
within the cross-section of a patient's vessel, wherein a stent is shown in a hidden 
view. 



_10- Docket No. ACS-53498 (21061) 

FIG. 12 depicts a longitudinal plan view of a stent delivery catheter 
assembly, including a detachable sheath of the present invention, which has been 
positioned proximate a dissected lining within a cross-section of a patient's vessel, 
wherein a stent is shown in a hidden view. 

FIG. 13 depicts a longitudinal plan view of a stent delivery catheter 
assembly, including a detachable sheath of the present invention, which has been 
positioned proximate a dissected lining within a cross-section of a patient's vessel, 
wherein the sheath has ruptured and begun to retract longitudinally. 

FIG. 14 depicts a longitudinal plan view of a stent delivery catheter 
assembly, including a detachable sheath of the present invention, which has been 
positioned proximate a dissected lining within a cross-section of a patient's vessel, 
wherein the sheath has fully retracted longitudinally and the balloon and stent are 
fully expanded. 

FIG. 15 depicts a longitudinal plan view depicting a partially withdrawn 
stent delivery catheter assembly, including a detachable sheath of the present 
invention, wherein a stent has been deployed within a cross-section of a patient's 
vessel. 

FIG. 16 depicts a longitudinal plan view of a catheter assembly 
including detachable sheath made in accordance with the present invention wherein 
the detachable sheath has been ruptured, thereby exposing a self-expanding stent 
which is mounted on the balloon portion of the catheter. 



_U_ Docket No. ACS-53498 (21061) 

DESCRIPTION OF THE PREFERRED EMBODIMENTS 

As shown in the drawings for purposes of illustration, the present 
invention is directed to a delivery catheter assembly including a detachable sheath for 
removably securing an endoprosthesis -- for example, a stent -- onto an expandable 
member - for example, a balloon - associated with the distal end portion of the 
catheter assembly. The improved catheter assembly overcomes many of the problems 
associated with prior delivery catheters regarding securing the endoprosthesis to the 
expandable member of the catheter. The detachable sheath of the present invention 
reliably and inexpensively secures the endoprosthesis to the expandable member 
while traversing the patient anatomy, yet provides for safe and easy deployment of the 
endoprosthesis at the target site in a body lumen. 

A focus of recent development work in the treatment of heart disease 
has been directed to endoprosthetic devices called stents. One method and system 
developed for delivering stents to desired locations within the patient's body lumen 
involves crimping a stent about an expandable member, such as a dilatation balloon 
on the distal end of a catheter, advancing the catheter through the patient's vascular 
system until the stent is in the desired location within a blood vessel, and then 
inflating the expandable member on the catheter to expand the stent within the blood 
vessel. However, retaining the stent in the proper location on the expandable member 
while advancing the catheter through the patient vasculature has been found to be 
difficult. The improved catheter assembly having a detachable sheath of the present 
invention solves this stent slippage problem. 

While the invention is described in detail as applied to the use of 
catheter assembly having a detachable sheath for positioning a stent in the coronary 
arteries, those skilled in the art will appreciate that the improved catheter assembly 
can be applied to a variety of endoprostheses for use in other body lumens and patient 
vasculature, such as, but not limited to, peripheral arteries and veins. Although the 



_ 12 . Docket No. ACS-53498 (21061) 

invention is described with respect to covering a stent on the balloon portion of a 
catheter, the invention is not so limited and includes protecting stents, grafts or other 
endoprostheses on any type of catheter used to deliver and implant such devices. 

With reference to the drawing figures, where different embodiments 
incorporating the invention have like elements, like reference numbers have been 
used. 

Referring now to the drawings and more particularly to FIGS. 1 and 2, 
there is shown a distal portion of an embodiment of a catheter assembly 20 
incorporating the features of the present invention. The catheter assembly includes an 
inner elongate tubular member 22 configured to encompass a guidewire 24 positioned 
to slide within an inner lumen of the elongate tubular member. A catheter tube 30 is 
disposed on and preferably secured to the elongate tubular member. The catheter tube 
includes an expandable member 31, for example a dilatation balloon, formed on or 
secured to its distal portion. The catheter tube further has a proximal portion 32, 
which may extend the length of the catheter assembly, culminating in a proximal 
portion of the catheter assembly, for example a sidearm (not shown), which may 
include an inflation port in fluid communication with the catheter tube, and may 
include a guidewire port in communication with a proximal end of the inner elongate 
tubular member. In addition, the catheter tube has a distal end 34 which is glued, 
bonded, heat shrunk or otherwise secured to and proximate of a distal end 23 of the 
elongate tubular member. 

The expandable member or balloon 31 is formed just proximal of the 
distal end 34 of the catheter tube 30. Alternatively, the balloon can be a separate 
element of the catheter assembly, which is secured to and in fluid communication with 
a lumen in the proximal portion of the catheter tube 32. In such a configuration, the 
elongate tubular member 22 is not a necessary element of the catheter assembly, and 
the guidewire 24 may be disposed within a separate lumen of the catheter tube. 



-13- Docket No. ACS-53498 (21061) 

The distal portion of the catheter assembly 20 further includes an 
endoprosthesis 50, such as a stent, crimped or otherwise disposed on the catheter tube 
30. The stent is positioned between the distal end 34 and the proximal portion 32 of 
the catheter tube, particularly on the expandable member 31. As shown in FIG. 2, the 
non-solid, lattice nature of many of the present day stent configurations may result in 
a non-uniform application of the stent elements on the balloon. Furthermore, to 
reduce the overall profile of the catheter assembly, the expandable member may be 
folded such that the cross-section of the expandable member is not circular in nature. 
In many stent delivery catheters, the expandable member is a dilatation balloon having 
been arranged in a multiple- fold or no-fold configuration prior to positioning the stent 
on the balloon. 

The improvement of the catheter assembly over the prior art is the 
addition of a detachable sheath 40 on the distal portion of the catheter assembly 20. 
The sheath is disposed over the endoprosthesis (stent) 50, and is also disposed over 
the expandable member (balloon) 3 1 of the catheter tube 30. An advantage of the 
detachable sheath is that it envelopes the endoprosthesis, preventing the endopros- 
thesis from contacting the patient's vasculature and from becoming dislodged from its 
position on the expandable member. 

The detachable sheath 40 has a proximal end 42, which may be glued, 
bonded, heat shrunk or otherwise secured to the proximal portion 32 of the catheter 
tube 30 just proximal of the expandable member 3 1 . Further, the sheath has a distal 
end 44 which may be glued, bonded, heat shrunk or otherwise secured to the distal 
end 34 of the catheter tube and/or to the distal end 23 of the elongate tubular member 
22. Alternatively, the proximal end of the detachable sheath may extend to and may 
be secured proximate the very proximal end of the catheter tube (FIG. 7A). In such a 
case, the sheath may be inflated separately of the expandable member. 

Referring to FIGS. 3-6, the detachable sheath 40 is configured to 
rupture upon expansion of the expandable member 3 1 of the catheter tube 30. For 



.14- Docket No. ACS-53498 (21061) 

example, the sheath may be configured to rupture at an inflation pressure of two 
atmospheres; whereas, the nominal inflation of the expandable member is eight 
atmospheres. To aid in the rupture at a specific portion of the sheath, the sheath may 
be scored or provided with one or more (a plurality) of perforations 46. The scoring 
or perforations may be placed at specific location of the sheath, for example, 
circumferential about the midline, to provide a specific detachment of the sheath into 
two halves (FIG. 3). Moreover, the sheath may be stretched over the stent 50 and 
catheter tube 30 prior to securing the sheath to the catheter, such that one of the 
broken halves of the sheath will retract towards the proximal portion 32 of the 
catheter tube, and the other broken halve will retract towards the distal end 34 of the 
catheter tube. This automatic retraction of the detachable sheath has the advantage 
over prior art sheaths that it does not require manipulation by the physician to displace 
the sheath from surrounding the stent. 

The scoring or perforations 46 in the sheath 40 may be made by any 
process known to those skilled in the art, such as with a sharp knife or razorblade, a 
laser, etc. The scoring and perforations, however, are not necessary features of the 
detachable sheath. Alternatively, the sheath may be weakened at a location where the 
sheath is desired to rupture. The sheath may be weakened by softening the desired 
area with heat, or otherwise deforming the micro-structure of the sheath material at 
the desired location. 

It should be appreciated to those skilled in the art that the location where 
the sheath is to rupture need not necessarily occur about the midline, as is shown in 
the Figures, to provide detachment of the sheath into two substantially equal halves. 
Rather, the scoring, preparations or weakening of the sheath can take place at other 
locations along the sheath without departing from the spirit and scope of the present 
invention. 

As shown in FIG. 4, introduction of inflation fluid (air, saline, etc.) 38 
into the catheter tube 30 causes the expandable member 3 1 to expand in an outwardly 



-15- Docket No. ACS-53498 (21061) 

(transverse) direction 56. The expansion of the expandable member causes the 
detachable sheath 40 to rupture, preferably creating two halves having edges 48, 
which is facilitated by the scoring of perforations 46 in the sheath. The expansion of 
the expandable member causes the edges of the sheath to move in a longitudinal 
5 direction 54 towards the proximal end 42 and the distal end 44 of the sheath, and 
towards the proximal portion 32 and distal end 34 of the catheter tube. As the 
expandable member expands and the sheath retracts, the stent 50 becomes exposed to 
the body lumen. Once the balloon is fully expanded, the stent also becomes fully 
expanded (FIG. 5). So as to not interfere with implantation of the stent, the broken 
lCP portions of the sheath should retract towards the proximal and distal ends of the 

catheter tube sufficiently to fully expose the stent. Such longitudinal movement is 
fli facilitated by the initial stretching of the sheath over the stent and the balloon. 

In many configurations of stent delivery catheter assemblies having a 
f~ catheter tube 30, the proximal and distal portions of the expandable member 3 1 will 
lfc expand first and to a greater degree than the middle portion of the expandable 
C member, which is restrained somewhat by the stent 50. As shown in FIG. 6, the 
p expandable member expands first at the proximal and distal edges. Expansion of the 
ends of the expandable member creates a longitudinal force 54 on the sheath 40, 
causing the sheath to rupture and the edges 48 to retract prior to any significant radial 
20 expansion 56 of the stent and middle portion of the expandable member. 

In an alternative embodiment of the stent delivery catheter 90 as shown 
in FIGS. 7 A and 7B, a longer sheath 40 is provided such that the proximal end 42 of 
the sheath is positioned outside of the patient and somewhat distal of the proximal 
portion (sidearm) 91 of the delivery catheter assembly. As before, the distal end 44 of 
25 the sheath is positioned just proximal of the distal end 92 of the catheter assembly. 

The catheter proximal portion (sidearm) includes a guidewire port 94 for receiving a 
proximal end 25 of a guidewire 24, and includes an inflation port 96 for introducing 
inflation fluid into the catheter tube 30 and the expandable member (balloon) 3 1 . The 



_16- Docket No. ACS-53498 (21061) 

sheath proximal end is secured to the proximal portion 32 of the catheter tube 
somewhat distal of the guidewire port and the balloon inflation port (sidearm). The 
proximal portion of the sheath is configured with an inflation port 100 positioned 
somewhat distal of the point of attachment of the sheath to the catheter tube. The 
inflation port may include a Luer lock or any other appropriate fitting for inflating the 
dedicated lumen with any inflation device. Another option is to mold an extension 
onto the sheath during its manufacture. The extension could be connected to a 
syringe or indeflator for inflation. Alternatively, the sheath could be made so that it 
does not have to be sealed to the catheter at the proximal attachment site, but rather 
has an open flap at that location. The flap could be clamped with a hemostat and the 
sheath inflated through a fitting attached to the sheath. When the distal end of the 
sheath detaches from the catheter due to the inflation, the physician could use the 
hemostat to retract the sheath proximally . 

As shown in FIG. 7B, the sheath distal end 44 is secured to the distal 
end 34 of the catheter tube 30 and/or to the distal end 23 of the elongate tubular 
member 22, in which the guidewire 24 is disposed. The sheath distal end is scored, 
perforated or otherwise weakened as described heretofore to permit the sheath distal 
end to break away from the catheter tube and elongate tubular member when inflation 
fluid 98 is introduced into the sheath 40. The perforations could be made in any other 
location that would allow pullback and/or detachment of the sheath. If the sheath can 
be stretched tightly enough, then there may be no need to perforate it and seal it. 
Rather, if the clearance between the inner surface of the sheath and the outer surface 
of the outer member is small enough, then fluid injected into the sheath inflation 
lumen could inflate the sheath while the fluid leaking out could provide the 
lubrication required to retract the sheath. Alternatively, a perforation could run the 
longitudinal length of the sheath with or without the need for distal perforation and 
seal. 



.17- Docket No. ACS-53498 (21061) 

The sheath 40 can be separately inflated at low pressure by introducing 
inflation fluid 98 into the sheath inflation port 100 until the sheath distal end 44 tears 
away and disengages from the distal end 34 of the catheter tube 30 and exposes the 
stent 50, Once inflated and detached, the sheath could be manually retracted toward 
the proximal end 91 of the stent delivery catheter in order to expose the stent. Pre- 
stretching the sheath over the catheter tube and the stent provides for automatic 
retraction of the sheath from the expandable member 3 1 and from the stent. The 
sheath can be further retracted by pulling on the proximal end 42 of the sheath by the 
physician. After the sheath is retracted from the expandable member and the stent, the 
expandable member can be separately inflated to its nominal pressure to deploy the 
stent. This alternative embodiment differs from the embodiment discussed herein 
regarding FIGS. 1-6 wherein the sheath and expandable member expand simultane- 
ously when the expandable member is inflated. This alternative embodiment of the 
sheath is best-suited to an over-the-wire system, as the sheath would interfere with 
using the exit notch of a rapid exchange system. 

The alternative embodiment shown in FIGS. 7 A & 7B allows the 
physician to advance the stent delivery system to the vicinity of the lesion and 
inflate/detach the sheath using the dedicated inflation lumen. Then, the physician can 
advance the stent into the lesion and deploy the stent. With the embodiment shown in 
FIGS. 1-6, the physician does not have this option since the sheath and stent inflate 
simultaneously. The second embodiment is potentially more deliverable than the first 
embodiment, since its profile can be reduced by removing the sheath prior to stent 
deployment. The longer sheath of the second embodiment could enhance its 
pushability due to the added bulk material. The inflation fluid could also be a drug 
(for instance collagenase) or any other substance that would be useful in treating a 
lesion prior to stent deployment. The device would not be used primarily for drug 
delivery, but rather the inflation fluid would leak out of the sheath as a consequence 



.18. Docket No. ACS-53498 (21061) 

of deployment. The sheath could be coated or surface- treated to enhance manual 
proximal retraction over the stent and catheter. 

The detachable sheath 40 is made from a suitable biocompatible 
material, for example, polymers and composites. Suitable non-stretchable materials 
include, but are not limited to, polyethylenes, polyethylene terephthalate (PET), 
poly amides such as nylon, polyesters and polytetrafluoroethylene (PTFE). If the 
sheath is to be stretched over the stent and expandable member, the sheath should be 
configured to have a durometer shore hardness of about 45D or below, and capable of 
elongation of at least three hundred percent. Suitable stretchable or elastomeric 
materials include, but are not limited to, aromatic and aliphatic polyurethanes, poly- 
etheretherketone (PEEK), polyester amides such as Pebax, copolyesters such as 
Arnitel, Hytrel and Pelprene, and expandable polytetrafluoroethylene (e-PTFE). One 
suitable thermoplastic polymer is C-FLEX, which is a trademarked product available 
from Concept Polymer Technologies of Largo, Florida. A suitable polyurethane is 
TECOPHILIC, which is a trademarked product available from Thermedics, of 
Woburn, Mass. Furthermore, in case one or more portions of the sheath break off into 
the patient's vasculature, the retaining device may be made from a biodegradable 
material, such as, but not limited to, polylactic acid (PLA), poly-L-lactic acid (PLLA), 
polyglycolic acid (PGA), fibrin, elastin and collagen. Other suitable materials can be 
used as are known to those skilled in the art. 

Where the sheath material causes the stent to unduly stick to the sheath, 
a lubricious coating may be applied to the inside of the sheath. Suitable lubricants 
include, but are not limited to polyethylene oxides, glycols and silicone based 
compounds. Suitable lubricants include MICROGLIDE and HYDROCOAT, 
trademarked products manufactured by Advanced Cardiovascular Systems, Inc. of 
Santa Clara, California. Alternatively, the inside or outside of the sheath could be 
plasma treated to allow attachment of functional groups and/or molecules which 
reduce or increase the friction between the sheath, stent and expandable member, as 



-19- Docket No. ACS-53498 (21061) 

well as the friction between the external layer of the sheath and any contact material 
Other suitable lubricants can be used as are known to those skilled in the art. 

One particularly suitable material that can be readily stretched and can 
be configured to rupture at about two atmospheres of inflation pressure is the 
polyurethane "ESTANE," a trademarked product available from BF Goodrich of 
Charlotte, North Carolina. The ESTANE sheath may be initially formed with an inner 
diameter of 0.032 inches (0.81 mm) and an outer diameter of 0.042 inches (1.07 
mm). The ESTANE sheath may be expanded to an inner diameter of 0.038 inches 
(0.974 mm) and an outer diameter of 0.046 inches (1.18 mm), by heating at 250 °F 
(120 °C) over a TEFLON - polytetrafluoroethylene (PTFE) - sheath having an outer 
diameter of 0.05 inches (1 .27 mm), using an air flow of twenty-five ft 3 /hr (0.71 m 3 /hr) 
and air pressure of eighty psi (5.5 atm). The expanded ESTANE tubing may then be 
scored with three equidistant slits along the circumference of the sheath, using a 
razorblade or similar sharp instrument. The proximal end of the sheath may then be 
secured the proximal portion of the expandable member using an adhesive, such as 
LOCTITE 3201, a trademarked product available from the Loctite Corporation. The 
sheath may then be pulled from two hundred to three hundred percent expansion 
elongation on the distal end. The distal end of the sheath may then may be laser 
sealed to the distal end of the expandable member or elongate tubular member. 

A stent delivery catheter assembly including the detachable sheath of the 
present invention can be configured by modifying commonly known stent delivery 
systems. As shown in FIG. 8, the catheter assembly may be configured as an over- 
the-wire (OTW) intravascular catheter 60. The OTW catheter includes a proximal 
portion (sidearm) 61 and a distal portion 62. The proximal portion includes a 
guidewire port 64 for receiving a proximal end 25 of a guidewire 24. The OTW 
catheter proximal portion also includes an inflation port 66. An inner elongate tubular 
member 22 extends from the OTW catheter proximal portion (sidearm) to the OTW 
catheter distal end, and is configured with a lumen for slidably receiving the guide- 



_20- Docket No. ACS-53498 (21061) 

wire. A catheter tube 30 is disposed over the elongate tubular member, and has a 
proximal portion 32 which extends from the sidearm to an expandable member 31 at 
the distal section of the catheter tube. The catheter tube is configured with an 
inflation lumen 36 in fluid communication with the inflation port. The catheter tube 
further has a distal end 34 secured to the distal end 23 of the elongate tubular member. 
A stent 50 is disposed on an expandable member 3 1 of the catheter tube, configured 
proximate the distal end of the catheter tube and the distal end of the elongate tubular 
member. A detachable sheath 40 is disposed over the stent and expandable member, 
and is secured to the distal portion of the OTW catheter. As will be appreciated by 
those of ordinary skill in the art, various forms of OTW catheters may be employed 
without deviating from the scope of the invention. 

As shown in FIG. 9, the catheter assembly may be configured as a rapid 
exchange (Rx) intravascular catheter 70. The Rx catheter includes a proximal portion 
71 and a distal portion 72. The Rx catheter proximal portion includes an inflation 
port 76 in fluid communication with a rigid member (hypotube) 78 connected to and 
in fluid communication with a proximal portion 32 of a catheter tube 30, having an 
inflation lumen 36. The catheter tube further has a distal end 34 secured to a distal 
end 23 of an elongate tubular member 22 within which is disposed a guidewire 24. 
The guidewire exits a distal end 74 of the elongate tubular member proximate the 
distal portion of the catheter tube. A stent 50 is disposed on an expandable member 
31 of the catheter tube, configured proximate the distal end of the catheter tube and 
the distal end of the elongate tubular member. A detachable sheath 40 is disposed 
over the stent and expandable member, and is secured to the distal portion of the Rx 
catheter. As will be appreciated by those of ordinary skill in the art, various forms of 
Rx catheters may be employed without deviating from the scope of the invention. 

As discussed above, the delivery catheter assembly 20, as described 
herein, can have an over-the-wire (OTW) or rapid exchange (Rx) configuration as 
more fully disclosed in, but not limited to, U.S. Patent No. 4,323,071 (Simpson et al.) 



_21- Docket No. ACS-53498 (21061) 

(OTW); U.S. Patent No. 4,573,470 (Samson et al.) (OTW); U.S. Patent No. 5,501,227 
(Yock) (Rx); U.S. Patent No. 5,061,273 (Yock) (Rx); and U.S. Patent No. 5,496,346 
(Horzewski et al.) (Rx). Likewise, the stent 50, as described herein, can have various 
configurations, and suitable stents include, but are not limited to, the ACS MULTI- 
LINK STENT sold by Advanced Cardiovascular Systems, Inc., Santa Clara, 
California; the NIR STENT sold by Boston Scientific, Natick, Massachusetts; and the 
MICRO STENT II and GFX sold by Arterial Vascular Engineering, Santa Rosa, 
California. The ACS MULTI-LINK STENT mounted on a rapid exchange delivery 
catheter is disclosed in U.S. Patent No. 5,514,154 (Lau et al.). 

When combined with a stent delivery catheter assembly, a detachable 
sheath of the present invention results in an improved process for delivering and 
implanting a stent to a desired location within a patient's vasculature. Figures 10 
through 15 illustrate, by way of example, a method of delivering and implanting a 
stent 50 mounted on a balloon 31 of a catheter tube 30, including an embodiment of 
the detachable sheath 40. While the drawing figures illustrate a rapid exchange (Rx) 
intravascular catheter 20, embodiments of the retaining device may also be used with 
an over-the-wire (OTW) intravascular catheter. 

The figures illustrate a situation in which the stent delivery catheter 
having a detachable sheath is used to support a dissected arterial lining to prevent the 
dissection from collapsing into the arterial passageway and impeding sufficient blood 
flow through the vessel. In addition, the stent delivery catheter having a detachable 
sheath may be used in a balloon angioplasty procedure in which a stent is used to 
support the vasculature to prevent restenosis. Furthermore, the procedures and 
devices described herein may be adapted by one of ordinary skill in the art to any 
procedure where a endoprosthesis is to be placed into a body lumen. 

As shown in FIG. 10, a catheter assembly 20 is provided with 
detachable sheath 40 covering a stent 50 removably secured on an expandable 
member 3 1 formed on or secured to a catheter tube 30. The detachable sheath is 



.22- Docket No. ACS-53498 (21061) 

secured to the catheter, as heretofore described. Referring to FIG. 1 1, the catheter 
assembly is inserted into the lumen of vessel of a patient's vasculature 80, such as a 
coronary artery, along a guidewire 24 having a distal end 26, which is previously 
positioned distal to the desired location 84 requiring support. The expandable 
member, including the stent covered by the detachable sheath, is then moved in a 
distal direction until the detachable sheath and stent are positioned proximate a 
dissected lining 82 at the desired location in the patient's vasculature (FIG. 12). 

As illustrated in FIG. 13, once the stent 50 is positioned at the desired 
location 84 of the vessel 80, the expandable member (balloon) 31 of the catheter tube 
30 is inflated. This may be accomplished, for example, by injecting inflation fluid 
under substantial pressure into a lumen of the catheter tube. Once a first pressure is 
realized, which is less than the nominal inflation pressure of the balloon, the detach- 
able sheath 40 ruptures. As the detachable sheath ruptures, the broken edges 48 of the 
detachable sheath retract longitudinally, thereby partially exposing the stent. As the 
balloon continues to expand to its nominal (second) pressure, the ruptured detachable 
sheath fully retracts away from the stent. Simultaneously, the stent continues to 
expand, until it is fully expanded and implanted in the vessel (FIG. 14). After the 
stent is fully expanded, the balloon is then deflated or otherwise contracted; however, 
the expandable stent remains implanted at the desired location in the vessel. Once the 
stent is no longer in contact with the catheter assembly, then the catheter tube, 
balloon, ruptured detachable sheath, and guidewire 24 are withdrawn from the 
vasculature (FIG. 13). 

Referring now to FIG. 16, a self-expanding stent 1 10 is shown 
positioned on a catheter assembly which is similar to the one shown in FIGS. 3-6. 
Therefore, like members have been designated with the same reference numerals in 
FIG. 16. As can be seen in FIG. 16, the detachable sheath 40 has a proximal end 42 
which may be glued, heat bonded, heat shrunk or otherwise secured to the proximal 
portion 32 of the catheter tube 30 just proximal of the expandable member 3 1 . 



_23- Docket No. ACS-53498 (21061) 

Likewise, the sheath 40 has a distal end 44 which may be glued, heat bonded, heat 
shrunk or otherwise secured to the distal end 34 of the catheter tube or to the distal 
end 23 of the elongate tubular member 22. Alternatively, the proximal end of the 
detachable sheath may extend to and may be secured proximate to the very end of the 
catheter tube. In such a case, the sheath may be inflated separately from the 
expandable member. 

The detachable sheath 40 shown in FIG. 16 is configured to rupture 
upon expansion of the expandable member 3 1 of the catheter tube 30. The detachable 
sheath 40 should be made from suitable material, such as the sheathing material 
described above, except that the sheath 40 may require additional strength to maintain 
the self-expanding stent 1 10 in its collapsed, unexpanded position while on the 
catheter. This is due to the outward radial force generated by the self-expanding stent 
on the sheath, which in this configuration would cause the stent to expand from the 
center outward. Therefore, the amount of force which must be developed by the 
expandable member 3 1 in order to rupture the detachable sheath 40 may be less than 
required to rupture a sheath which covers a balloon expandable stent since the force 
developed by the self-expanding stent 110 also assists in rupturing the sheath 40. 

As can be seen in FIG. 16, the dynamics behind the expansion of the 
self-expanding stent 1 10 are a bit different than the dynamics when deploying a 
balloon expandable stent. As the inflatable member 3 1 is inflated to rupture the 
sheath 40, the expandable stent 110 immediately proceeds to expand radially outward 
from the center, as can be seen in FIG. 16. This is different from the configuration of 
the catheter as shown in FIG. 6 as the balloon expandable stent is being expanded by 
the expandable member 31. The dynamics in deploying a self-expanding stent 110 
from the catheter assembly helps prevent the stent 1 10 from "jumping off of the 
catheter as the sheath 40 is being ruptured by the inflatable member 31. As a result, 
the placement of the self-expanding stent 110 within the patient's vasculature should 
be quite accurate since the initial expansion of the extension of the central section of 



.24- Docket No. ACS-53498 (21061) 

the stent should help prevent the "jumping" phenomena from occurring during stent 
deployment. 

Referring back to FIG. 16, as the sheath 40 is ruptured, the expandable 
member 3 1 does not need to be inflated further to deploy the self-expanding stent 
since the ruptured sheath 40 should immediately retract back towards its proximal 
end 42 and distal end 44, allowing the self-expanding stent 1 10 to fully deploy. 
However, it should be appreciated by one skilled in the art that the deflatable member 
31 could be further inflated, if desired, to ensure that the self-expanding stent 1 10 is 
folly expanded into its deployed condition with the patient's vasculature. 

The catheter assembly 20 with a self-expanding stent 110 could be 
similarly deployed in the patient's vasculature as is shown in the sequence depicted in 
FIGS. 11-15. The expandable member 3 1 of the catheter assembly 20 may have a 
limited role in deploying the self-expanding stent 110 within the patient's 
vasculature, in that the expandable member could be used only to rupture the 
detachable sheath to initiate the deployment of the self-expanding stent 110. 
Alternatively, the expandable member 3 1 could be continued to be inflated to ensure 
that the self-expanding stent 1 10 is fully deployed within the vasculature, as 
addressed above. After the self-expanding stent has been fully deployed within the 
vasculature, the catheter assembly 20, with its expandable member and ruptured 
sheath can be withdrawn, along with the guide wire, from the patient's vasculature. 

It should be appreciated that the location of the perforations which are 
placed on the sheath 40 need not necessarily be located directly at the midline of the 
sheath 40, as is disclosed in FIG. 16. Rather, the perforations or scoring could be 
done at other locations along the sheath 40 without departing from the spirit and 
scope of the present invention. 

The dimensions of the intravascular catheter will generally follow the 
dimensions of intravascular catheters used in angioplasty procedures in the same 
arterial location. Typically, the length of a catheter assembly for use in the coronary 



-25- Docket No. ACS-53498 (21061) 

arteries is about one hundred thirty- five to one hundred fifty centimeters, the outer 
diameter of the catheter expandable member is about one millimeter, the length of the 
balloon is typically about two centimeters and the inflated diameter of the balloon is 
about one to about five millimeters, depending upon the application. Catheter 
dimensions for peripheral use will vary, and is known in the art. The materials of 
construction of the catheter assembly, catheter tube and expandable member may be 
selected, for example, from those used in conventional balloon angioplasty catheters. 
Furthermore, the specific dimensions and materials of construction of the detachable 
sheath are provided as examples, and substitutes are readily contemplated which do 
not depart from the invention. 

While the present invention has been described herein in terms of 
delivering an expandable stent to a desired location within a patient's blood vessel, 
the delivery catheter can also be employed to deliver stents to locations within other 
body lumens so that the stents can be expanded to maintain the patency of those body 
lumens. In addition, the detachable sheath may be used to secure self- expanding 
stents to delivery catheters prior to deployment. 

Thus, the detachable sheath of the present invention provides an 
improved stent delivery catheter assembly having an efficient means to removably 
secure a stent onto an expandable member for delivery and insertion into a patient's 
vasculature. The detachable sheath adequately covers the stent and the catheter's 
expandable member during traverse of the patient's vasculature, while adding little or 
no additional outer diameter profile to the catheter assembly. The sheath prevents the 
stent and stent edges from catching on the vasculature or previously deployed stent as 
the catheter assembly traverses the patient's anatomy. Similarly, the detachable sheath 
aids in retaining the stent while advancing through difficult lesions, without unduly 
decreasing the flexibility and steerability of the catheter assembly, or otherwise 
compromising the deliverability of the stent. The detachable sheath can be integrated 
into current stent delivery platforms and can be E-beam sterilized. Thus, a long felt 



_26- Docket No. ACS-53498 (21061) 

need in the industry has been solved by the catheter assembly having a detachable 
sheath as disclosed herein. 

It will be apparent from the foregoing that, while particular forms of the 
invention have been illustrated and described, various modifications can be made 
without departing from the spirit and scope of the invention. Accordingly, it is not 
intended that the invention be limited, except as by the appended claims. 



WHAT IS CLAIMED IS: 



-27- 



DocketNo. ACS-53498 (21061) 



1 . A catheter assembly for delivering an endoprosthesis within a 
body lumen, comprising: 

a catheter having a proximal end portion and a distal end portion; 
an expandable member associated with the distal end portion of 

the catheter; 

an endoprosthesis disposed on the expandable member; and 
a sheath disposed on the catheter and over the endoprosthesis, 

wherein the sheath is configured to rupture during expansion of the expandable 

member. 



2. The catheter assembly of claim 1, wherein: 

the sheath includes a weakened section configured to rupture 
during expansion of the expandable member. 



3. The catheter assembly of claim 1 ? wherein: 

the sheath includes a plurality of circumferential perforations. 



4. 

member. 



The catheter assembly of claim 1 ? wherein: 

the sheath is stretched over and secured to the expandable 



5. 



of the catheter. 



_28- Docket No. ACS-53498 (21061) 

The catheter assembly of claim 1, wherein: 

the sheath is stretched over and secured to the distal end portion 



6. The catheter assembly of claim 1 ? wherein: 

the sheath has a proximal end secured to the proximal end 
portion of the catheter, and the sheath has a distal end removably secured to the distal 
end portion of the catheter. 

7. The catheter assembly of claim 6, wherein: 

the sheath is stretched prior to securing the sheath to the catheter. 

8. The catheter assembly of claim 1, wherein: 

the expandable member includes an inflatable dilatation balloon. 

9. The catheter assembly of claim 1 ? wherein: 
the endoprosthesis is a stent. 

10. The catheter assembly of claim 9, wherein: 
the stent is self-expanding. 

1 1 . The catheter assembly of claim 1, wherein: 

the catheter includes an over-the-wire intravascular catheter. 



-29- 



DocketNo. ACS-53498 (21061) 



12. The catheter assembly of claim 1, wherein: 

the catheter includes a rapid-exchange intravascular catheter. 

13. The catheter assembly of claim 1, wherein: 

the sheath is formed from an elastomeric material. 

14. The catheter assembly of claim 1, wherein: 

the sheath is formed from ESTANE with a shore hardness of 

45D or lower. 

15. The catheter assembly of claim 1 ? wherein: 

the sheath is formed from a biodegradable material. 

16. The catheter assembly of claim 1, wherein: 

the sheath is formed from a material selected from the group 
consisting of polyurethanes, polyetheretherketone, poly ether amides, copoly esters, 
and expandable polytetrafluoroethylene. 

17. The catheter assembly of claim 1, wherein: 

the sheath is formed from a material selected from the group 
consisting of poly ethylenes, polyamides, polyesters, polyether amides, polyurethane, 
copolyesters, and polytetrafluoroethylene. 



-30- 



DocketNo. ACS-53498 (21061) 



1 8. An apparatus for delivering an endoprosthesis within a body 
lumen, comprising: 

an endoprosthesis; 

means for delivering the endoprosthesis within a body lumen, the 
means for delivering having a proximal end portion and a distal end portion; 

means for expanding the endoprosthesis, the means for 
expanding associated with the distal end portion of the means for delivering, wherein 
the endoprosthesis is disposed on the means for expanding; and 

means for retaining the endoprosthesis, the means for retaining 
being disposed on the means for delivering and over the endoprosthesis, wherein the 
means for retaining is configured to detach from the means for delivering when 
inflation fluid is introduced into the means for expanding. 



19. The apparatus of claim 18, wherein: 

the means for retaining includes a weakened section configured 
to rupture during expansion of the means for expanding. 



20. The apparatus of claim 18, wherein: 

the means for retaining includes a plurality of circumferential 

perforations. 



21. The apparatus of claim 18, wherein: 



-31- 



DocketNo. ACS-53498 (21061) 



the means for retaining is stretched over and secured to the means 

for expanding. 

22. The apparatus of claim 18, wherein: 

the means for retaining is stretched over and secured to the distal 
end portion of the means for delivering. 

23. The apparatus of claim 18, wherein: 

the means for retaining has a proximal end secured to the 
proximal end portion of the means for delivering, and the means for retaining has a 
distal end secured to the distal end portion of the means for delivering. 

24. The apparatus of claim 23, wherein: 

the means for retaining is stretched prior to securing the means 
for retaining to the means for delivering. 



25. 



The apparatus of claim 18, wherein: 

the means for expanding includes an inflatable dilatation balloon. 



26. 



The apparatus of claim 18, wherein: 
the endoprosthesis is a stent. 



27. 



-32- 

The apparatus of claim 1 8, wherein: 
the stent is self-expanding. 



Docket No. ACS-53498 (21061) 



28. The apparatus of claim 18, wherein: 

the means for delivering includes an over-the-wire intravascular 

catheter. 

29. The apparatus of claim 18, wherein: 

the means for delivering includes a rapid-exchange intravascular 

catheter. 

30. The apparatus of claim 1 8, wherein: 

the means for retaining is formed from an elastomeric material. 

3 1 . The apparatus of claim 1 8, wherein: 

the means for retaining is formed from ESTANE. 

32. The apparatus of claim 18, wherein: 

the means for retaining is formed from a biodegradable material. 

33. The apparatus of claim 18, wherein: 



.33- Docket No. ACS-53498 (21061) 

the means for retaining is formed from a material selected from 
the group consisting of polyurethanes, polyetheretherketone, polyether amides, 
polyurethane, copolyesters, and expandable polytetrafluoroethylene. 



34. The apparatus of claim 18, wherein: 

the means for retaining is formed from a material selected from 
the group consisting of poly ethylenes, poly amides, polyesters, polyether amides, 
polyurethane, copoly esters, and polytetrafluoroethylene. 



35. A catheter assembly for delivering a stent within a patient's 
vasculature, comprising: 

a catheter tube having a proximal end portion and a distal end 

portion; 

a balloon formed on the distal end portion of the catheter tube; 
a stent disposed on the balloon; and 

a sheath secured to the distal end portion of the catheter tube, 
wherein the sheath is stretched over the balloon and over the stent, and wherein the 
sheath includes a weakened section configured to rupture during inflation of the 
balloon. 



36. 

perforations. 



The catheter assembly of claim 35, wherein: 

the weakened section comprises a plurality of circumferential 



_34- Docket No. ACS-53498 (21061) 

37. The catheter assembly of claim 36, further comprising: 

a guidewire and an elongate tubular member having a proximal 
end portion and a distal end portion, the guidewire being slidably disposed within a 
lumen of the elongate tubular member, the elongate tubular member being disposed 
within the catheter tube, and the distal end portion of the catheter tube being secured 
to the distal end portion of the elongate tubular member. 

38. The catheter assembly of claim 35, wherein: 

the catheter assembly is configured as an over-the-wire 
intravascular catheter assembly. 

39. The catheter assembly of claim 35, wherein: 

the catheter assembly is configured as a rapid-exchange 
intravascular catheter assembly. 

40. The catheter assembly of claim 35, wherein: 

the sheath is formed from an elastomeric material. 

4 1 . The catheter assembly of claim 35, wherein: 
the sheath is formed from ESTANE. 



42. The catheter assembly of claim 35, wherein: 

the sheath is formed from a biodegradable material. 



-35- 



DocketNo. ACS-53498 (21061) 



43. The catheter assembly of claim 35, wherein: 

the sheath is formed from a material selected from the group 
consisting of polyurethanes, polyetheretherketone, polyether amides, copolyesters, 
and expandable polytetrafluoroethylene. 



44. The catheter assembly of claim 35, wherein: 

the sheath is formed from a material selected from the group 
consisting of poly ethylenes, polyamides, polyesters and polytetrafluoroethylene. 



45. A catheter assembly for delivering a stent within a patient's 

vasculature, comprising: 

a catheter tube having a proximal end portion and a distal end 

portion; 

a balloon formed on the distal end portion of the catheter tube; 
a stent disposed on the balloon; and 

a sheath having a proximal end portion positioned proximate the 
proximal end portion of the catheter tube, the sheath further having a distal end 
portion configured with a weakened section, the distal end portion of the sheath being 
secured to the distal end portion of the catheter tube. 



46. The catheter assembly of claim 45, further comprising: 

an inflation port positioned proximate the proximal end portion 
of the sheath and in fluid communication with the sheath, the proximal end portion of 



_36- Docket No. ACS-53498 (21061) 

the sheath being secured to the proximal end portion of the catheter tube, wherein the 
sheath is stretched prior to securing the sheath to the catheter tube. 

47. The catheter assembly of claim 46, wherein: 

the weakened section comprises a plurality of perforations. 

48. The catheter assembly of claim 47, further comprising: 

a guidewire and an elongate tubular member having a proximal 
end portion and a distal end portion, the guidewire being slidably disposed within a 
lumen of the elongate tubular member, the elongate tubular member being disposed 
within the catheter tube, and the distal end portion of the catheter tube being secured 
to the distal end portion of the elongate tubular member. 

49. The catheter assembly of claim 45, wherein: 

the catheter assembly is configured as an over-the-wire 
intravascular catheter assembly. 

50. The catheter assembly of claim 45, wherein: 

the catheter assembly is configured as a rapid-exchange 
intravascular catheter assembly. 



5 1 . The catheter assembly of claim 45, wherein: 

the sheath is formed from an elastomeric material. 



-37- 



DocketNo. ACS-53498 (21061) 



52. 



The catheter assembly of claim 45, wherein: 
the sheath is formed from ESTANE. 



53. 



The catheter assembly of claim 45, wherein: 

the sheath is formed from a biodegradable material. 



54. The catheter assembly of claim 45 , wherein: 

the sheath is formed from a material selected from the group 
consisting of polyurethanes, polyetheretherketone, polyether amides, copolyesters, 
and expandable polytetrafluoroethylene. 

55 . The catheter assembly of claim 45, wherein: 

the sheath is formed from a material selected from the group 
consisting of poly ethylenes, poly amides, polyesters, polyether amides, copolyesters, 
and polytetrafluoroethylene. 

56. A catheter assembly for delivering a self-expanding within a 

body lumen, comprising: 

a catheter having a proximal end portion and a distal end portion; 
an expandable member associated with the distal end portion of 

the catheter; and 



_ 3 g. Docket No. ACS-53498 (21061) 

a sheath disposed on the catheter and adapted to extend over the 
self-expanding stent when the self-expanding stent is in its collapsed position, 
wherein the sheath is configured to rupture during expansion of the expandable 
member. 



57. The catheter assembly of claim 56, wherein: 

the sheath includes a weakened section configured to rupture 
during expansion of the expandable member. 



58. The catheter assembly of claim 56, wherein: 

the sheath includes a plurality of circumferential perforations. 



59. The catheter assembly of claim 56, wherein: 

the sheath is stretched over and secured to the expandable 



member. 



60. The catheter assembly of claim 56, wherein: 

the sheath is stretched over and secured to the distal end portion 

of the catheter. 



6 1 . The catheter assembly of claim 56, wherein: 

the sheath is stretched prior to securing the sheath to the catheter 
over the self-expanding stent. 



-39- 



DocketNo. ACS-53498 (21061) 



62. A method of delivering an endoprosthesis into a desired location 
within a body lumen, the method comprising: 

providing a catheter assembly including a catheter having a 
proximal end portion and a distal end portion, an expandable member associated with 
the distal end portion of the catheter, an endoprosthesis disposed on the expandable 
member, and a sheath disposed on the catheter and over the endoprosthesis, wherein 
the sheath is configured to rupture during expansion of the expandable member; 

advancing the distal end portion of the catheter, the sheath, the 
expandable member and the endoprosthesis though the body lumen to a desired 
location; 

expanding the expandable member so as to rupture the sheath; 
further expanding the expandable member so as to expand the 
endoprosthesis at the desired location; 

contracting the expandable member; and 

withdrawing the catheter, the expandable member, and the sheath 
from the body lumen. 

63. A method of delivering a stent into a desired location within a 
patient's vasculature, the method comprising: 

providing a catheter assembly including a catheter tube having a 
proximal end portion and a distal end portion, a balloon formed on the distal end 
portion of the catheter tube, a stent disposed on the balloon, and a sheath secured to 
the distal end portion of the catheter tube, wherein the sheath is stretched over the 
balloon and over the stent, and wherein the sheath includes a weakened section 
configured to rupture during inflation of the balloon; 



_4Q- Docket No. ACS-53498 (21061) 

advancing the distal end portion of the catheter tube, the sheath, 
the balloon and the stent though the vasculature to a desired location; 

inflating the balloon to a first pressure so as to rupture the sheath; 
further inflating the balloon so as to expand the stent into the 

desired location; 

deflating the balloon; and 

withdrawing the catheter tube, the balloon and the sheath from 

the vasculature. 



64. A method of delivering a stent into a desired location within a 
patient's vasculature, the method comprising: 

providing a catheter assembly including a catheter tube having a 
proximal end portion and a distal end portion, a balloon formed on the distal end 
portion of the catheter tube, a stent disposed on the balloon, a sheath having a 
proximal end portion secured to the proximal end portion of the catheter tube, the 
sheath further having a distal end portion configured with a weakened section, the 
distal end portion of the sheath being secured to the distal end portion of the catheter 
tube such that the sheath is stretched prior to securing the sheath to the catheter tube, 
and an inflation port positioned proximate the proximal end portion of the sheath and 
in fluid communication with the sheath; 

advancing the distal end portion of the catheter tube, the distal 
end portion of the sheath, the balloon and the stent though the vasculature to a desired 
location; 

inflating the sheath so as to disengage the sheath from the distal 
portion of the catheter tube; 

inflating the balloon so as to expand the stent into the desired 

location; 



.41- Docket No. ACS-53498 (21061) 

deflating the balloon; and 

withdrawing the catheter tube, the balloon and the sheath from 

the vasculature. 



„42- Docket No. ACS-53498 (21061) 

ABSTRACT 



A catheter assembly for delivering an endoprosthesis within a body 
lumen. A delivery catheter assembly is provided which includes a detachable sheath 
for removably securing an endoprosthesis, for example a stent, onto an expandable 
5 member, for example, a dilatation balloon. The detachable sheath is associated with 
the distal end portion of the catheter assembly having an expandable member therein, 
whereby inflation of the expandable member ruptures the detachable sheath, thereby 
exposing the stent for implantation into a body lumen. Alternatively, the detachable 
O sheath may be inflated separately from the expandable member, and/or may be 
30 manually retracted from the stent. The detachable sheath prevents movement of the 
ftj stent relative to the catheter assembly during deployment in a body lumen, such as a 

patient's vasculature, by covering the stent until the stent is positioned at a desired 
" location within the body lumen. The catheter assembly is inserted into the vasculature 

and manipulated so that the stent is positioned proximate a desired location in the 
Q5 vasculature, such as at a lesion or stenosis in a coronary artery. The detachable sheath 
□ protects the stent and the expandable member while traversing the vasculature, and 

the sheath automatically retracts or is manually retracted prior to implanting the stent. 



178570.4 



J/9 



ACS-53498 




ACS-53498 




ACS-53498 




ACS-53498 




ACS-53498 



6/9 




ACS-53498 




8/9 




ACS-53498 




Docket No. ACS-53498 (21060) 
Page 1 of 5 



DECLARATION AND POWER OF ATTORNEY 
FOR PATENT APPLICATION 



As the below named inventors, we hereby declare that: 

Our residences, post office addresses and citizenship are as stated below next to our 
names, Brent Belding, Brian P. Cahill, Jeffrey T. Ellis, Richard J. Foust, Arkady Kokish, Florencia 
Lim and Chi Long. 

We believe we are original, first and joint inventors of the subject matter which is 
claimed and for which a patent is sought on the invention entitled DETACHABLE SHEATH TO 
PROVIDE PRE-DEPLOYMENT STENT SECURITY AND ENHANCED DELIVERY 
PRECISION, the specification of which (check one) 
X is attached hereto 

was filed on 

Application Serial No. 

and was amended on (or amended through) 

(if applicable) 

We hereby state that we have reviewed and understand the contents of the 
above-identified specification, including the claims, as amended by any amendment(s) referred to 
above. 

We acknowledge the duty to disclose information which is material patentability as 
defined in Title 37, Code of Federal Regulations, Sec. L56. 



Docket No. ACS-53498 (21060) 
Page 2 of 5 



We hereby claim foreign priority benefits under Title 35, United States Code, Sec. 
1 1 9 (a)-(d) of any foreign application(s) for patent or inventor's certificate listed below and have also 
identified below any foreign application for patent or inventor's certificate having a filing date before 
that of the application on which priority is claimed: 

Prior Foreign Application(s) Priority Claimed 

Number Country Dav/Month/Year filed Yes No 

None 

We hereby claim the benefit under Title 35, United States Code, Sec. 1 19(e) of any 
United States provisional application(s) listed below and, insofar as the subject matter of each of the 
claims of this application is not disclosed in the prior United States application in the manner 
provided by the first paragraph of Title 35, United States Code, Sec. 1 12, we acknowledge the duty 
to disclose material information as defined in Title 37, Code of Federal Regulations, Sec. 1 .56 which 
became available between the filing date of the prior application and the national or PCT 
international filing date of this application. 

Appln. Serial No. Filing Date Status (patented, pendin g, abandoned') 

None 

We hereby declare that all statements made herein of our own knowledge are true and 
that all statements made on information and belief are believed to be true; and further that these 
statements were made with the knowledge that willful false statements and the like so made are 
punishable by fine or imprisonment, or both, under Section 1001 of Title 18 of the United States 
Code and that such willful false statements may jeopardize the validity of the application or any 
patent issued thereon. 



Docket No. ACS-53498 (21060) 
Page 3 of 5 



We hereby appoint the following attorneys to prosecute this application and to 



transact all business in the Patent and Trademark Office connected therewith: 



EARL A. BRIGHT II, Registration No. 37,045; THOMAS A HASSING, 
Registration No. 36,159; TIM L. KITCHEN, Registration 41,900; PHILIP S. YIP, 
Registration 37,265; RICHARD A. BARDIN, Registration No. 20,365; GILBERT 
G. KOVELMAN; Registration No. 19,552; JOHN S. NAGY, Registration No. 
30,664; THOMAS H. MAJCHER, Registration No. 31,119; THOMAS A. RUNK, 
Registration No. 30,679; RONALD E. PEREZ, Registration No. 36,891; JOHN V. 
HANLEY, Registration No. 38,171; JOHN K. FITZGERALD, Registration No. 
38,881; and PAUL Y. FENG, Registration No. 35,510. 

Direct all telephone calls to Thomas H. Maj cher at telephone number (3 1 0) 824-5 5 5 5 . 



Address all correspondence to: 



FULWIDERPATTON LEE & UTECHT, LLP 
Howard Hughes Center 
6060 Center Drive 
Tenth Floor 
Los Angeles, California 90045 



Full name of first inventor: Brent Belding 





Citizenship: USA 



Post Office Address: 586 Dublin Way, 0mm) vale, California 94087 1 



65S 




Docket No. ACS-53498 (21060) 
Page 4 of 5 



Full name of second inventor: Brian P. Cahill 



Inventor's signature: 




Date: 3/ 2000 

Residence: //Zd Feu. 57, R^Ctsco, Ca 

Citizenship: 

Post Office Address: 



Full name of third inventor: Jeffrey T. Ellis 
Inventor's signature: ^ffj^ ^ ' 
Date: 1*7^ 2000 ^ . 

Residence: Me untain Vie w, California 

Citizenship: USA \<P 

Post Office Address: 1953-G alifornia Stre efr #14, Mu i ui l din View, Cdlif u mid 94040 

1> u «ccck Si-reef-^ # 3» ? - <?■ <To_n Fro. «c r sc. o^CA «? 4l 3 1 



Full name of fourth inventor: Richard J. Foust 
Inventor's signature: 



1 inventor: Richard J. roust 



Date: % / < ,2000 fpfy,/„ 

Residence: Mounlaiii View, California 
Citizenship: USA 

Post Office Address: 2Q*»Sa iM; Julien Court, Momilaiii View, Cali fuiii ia 910 13 



Docket No. ACS-53498 (21060) 
Page 5 of 5 




Full name of fifth inventor: Arkady Kglrish 
Inventor's signature: 
Date: 7 / 1/ .2000 
Residence: Los Gatos, California 
Citizenship: USA 

Post Office Address: 105 Griffith Place, Los Gatos, California 95030 



Full name of sixth inventor: Florencia Lim 
Inventor's signature: 
Date: ^8 , 2000 

Residence: Union City, California 
Citizenship: USA 

Post Office Address: 2710 Cherry Blossom Way, Union City, Californai 94587 




Full name of seventh inventor: Chi Long . 

Inventor's signature: ( JiA/U^ U7V°L ^^ 

Date: ifUi .2000 

Residence: San Jose, California 

Citizenship: USA 

Post Office Address: 2856 Plumas Drive, San Jose, California 95121 

180288.1